To solve this problem, first add the two parts of the ratio. 9 + 5 = 14. Then divide 70 by 14 to get 5. Since the total is 5 times the ratio total, multiply both sides of the ratio by 5. The result is 45 : 25. If you add them together, you get a total of 70. Therefore, there are 25 boys in the class.
Step-by-step explanation: 3 + 5 = 8 boys total 4 + 8 = 12 girls total 8 + 12 = 20 kids total. To find out the probability of randomly choosing a boy you have to do the number of boys over the total amount of kids (8/20) which will equal 40%.
